Swivel Apparatus For Fixed Casing Ram

ABSTRACT

The present application pertains to a swivel insertable into a casing ram. The swivel comprises an inner mandrel having an upper end section and a lower end section configured to be operably connectable and rotatable with an upper workstring section and a lower workstring section, the inner mandrel comprising a longitudinal passage forming a continuation of a passage in the workstring. An outer housing is configured to seal the inner mandrel inside the outer housing. The outer diameter of the outer housing and the length of the outer housing is configured to fit a casing ram. In contrast to prior art tools placed within annular blowout preventers which have limited differential pressure ranges, the instant device allows for differential pressure during operation as high as 10,000 psi or more. The instant devices also may allow for aggressive frac pack treatments and facilitate reverse out operations.

TECHNICAL FIELD

The present inventions are directed to swivels configured for a casingram as opposed to an annular blowout preventer (BOP) and allowing fordifferential pressure during operation as high as 10,000 pounds persquare inch (psi) or more.

BACKGROUND AND SUMMARY

Circulating a well under pressure is usually accomplished by closing theannular BOP to seal on the workstring. The friction between the annularseal and the workstring creates high axial loads that complicaterotating and reciprocating the workstring. At the end of a frac packtreatment the workstring and downhole service tool must be reciprocatedupward under pressure to reverse circulate proppant laden fluid out ofthe workstring. The added friction when stripping through the annularBOP complicates precise downhole service tool movement and positioning.Use of a slick outer diameter workstring and grease can reduce frictionbetween the annular BOP and workstring; however, friction can still besignificant.

Another concern is the pressure rating of the annular BOP. In deepwaterfrac packs, reverse circulating pressures can potentially exceed theannular BOP rating. When it is anticipated that the annular BOP pressurerating will be exceeded, the frac pack design must be more conservativeto mitigate a high pressure situation.

Prior art devices such as the Mako MAPTool™ and Deltascope® aredescribed in, for example, U.S. Pat. No. 10,988,989 which isincorporated herein by reference. Such prior art devices facilitaterotating and reciprocating a workstring in a well that is underpressure. Such tools generally have an outer housing and a slick innermandrel. The slick inner mandrel is sealed inside the outer housing. Theouter housing is positioned and sealed in an annular BOP. Thus, the toolis static while allowing the inner mandrel to rotate and reciprocatewith minimal friction even at high pressure differential. In thismanner, the annular BOP seals on the outer housing of the device toreduce friction.

While these prior art devices may address the axial load concern ofstripping through the annular BOP, they unfortunately do not address thepressure rating limit of the annular BOP. It would be desirable if newtools and methods could be designed that would allow higher differentialpressures such that pressure during operations are not limited to therating limit of an annular BOP which may be only 5,500 psi. It would beadvantageous if such new tools and methods allowed for aggressive fracpack treatments to maximize production rate and ultimate recovery from awell. It would further be desirable if such new tools and methodsfacilitated reverse out operations following a frac pack for bothefficiency and effectiveness.

The novel tools and methods described herein accomplish at least one ormore of the aforementioned needs. That is, the tools and methods of thepresent application may allow for differential pressure during operationas high as 10,000 psi or more. They also may allow for aggressive fracpack treatments and facilitate reverse out operations.

In one embodiment, the application pertains to a swivel insertable intoa casing ram of a workstring. The swivel comprises an inner mandrel 10having an upper end section and a lower end section. The upper endsection is configured to be operably connectable and rotatable with anupper workstring section and the lower end section is configured to beoperable connected to a lower workstring section. The inner mandrelcomprises a longitudinal passage forming a continuation of a passage inthe workstring. The outer housing has an outer diameter and a lengthconfigured to fit a casing ram while allowing the function of associatedcasing shear rams and variable bore rams. The outer housing isconfigured to seal the inner mandrel inside the outer housing. The innermandrel is configured to slide up and down within the outer housing androtate within the outer housing. In this manner, use of the novel toolwithin a casing ram may allow for a differential pressure duringoperation as high as 10,000 psi or more.

In another embodiment, the inner mandrel further comprises a locatorrecess. This locator recess may be configured to facilitate placement ofthe swivel within a casing ram.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the above-recited and otheradvantages and features can be obtained, a more particular descriptionof the subject matter briefly described above will be rendered byreference to specific embodiments which are illustrated in the appendeddrawings. Understanding that these drawings depict only typicalembodiments and are not therefore to be considered to be limiting inscope, embodiments will be described and explained with additionalspecificity and detail through the use of the accompanying drawings inwhich:

FIG. 1 shows a tool for rotating and reciprocating a workstring in awell that is under pressure and configured to be employed in a casingram as opposed to an annular blowout preventer (BOP).

FIG. 2A shows a prior art tool that is configured to be in an annularblowout preventer (BOP).

FIG. 2B shows a tool of the present application which can be employed ina casing ram.

FIG. 3 shows a modification to a top portion of the prior art tool.

DETAILED DESCRIPTION

Exemplary embodiments of the invention will now be described in order toillustrate various features of the invention. The embodiments describedherein are not intended to be limiting as to the scope of the invention,but rather are intended to provide examples of the components, use, andoperation of the invention.

FIG. 1 shows a tool of the present application for rotating andreciprocating a workstring in a well that is under pressure. The toolgenerally has an inner mandrel 10, an upper seal 20, outer housing 30,and lower seal 40. The tool is designed such that the outer diameterarea 50 of the housing fits within casing rams as opposed to the priorart tools that are sized and configured to fit where an annular blowoutpreventer closes and seals.

As shown in FIG. 1 , tools of the present application generally have anouter housing 30 and a slick inner mandrel 10. The slick inner mandrel10 is sealed inside the outer housing 30. The outer housing 30 ispositioned and sealed in a casing ram. The sealing occurs in outerdiameter area 50. Thus, in contrast to prior art tools the tools of thepresent application, among other differences, have an outer diameter ofthe outer housing and a length of the outer housing configured to fit acasing ram. The tool are further configured to allow the function ofassociated casing shear rams and variable bore rams. In this manner thecasing ram seals on the outer housing of device to reduce friction whileallowing differential pressures during operation as high as 12,500 psior more.

FIG. 2A shows the prior art tool of FIG. 1 within an annular blowoutpreventer 100 wherein blind shear rams 110, casing shear rams 120, uppervariable bore rams 130, casing rams 140, lower variable bore rams 150,and test rams are present below the annular blow out preventer.

In contrast to the prior art tool that is used in the annular blowoutpreventer, the present application pertains to a tool that is configuredto be placed within the casing rams 140 as shown in FIG. 2B.

One advantage of using a fixed casing ram vs. the annular BOP is theability to go to higher differential pressures during operation. Forexample, the maximum differential pressure when using the annular BOPmay be 5,500 psi. When using the fixed casing ram, the differentialpressure could go as high as 10,000 psi. The higher differentialpressure capability is beneficial particularly when reverse circulatingproppant laden fluid out of a workstring following frac pack operations.

The increased pressure rating afforded by designing the instantlydescribed tools so that they may be placed in a fixed casing ram insteadof the annular BOP allows for aggressive frac pack treatments tomaximize production rate and expected ultimate recovery from the well.The tools of this application employed in a casing ram may alsofacilitate reverse out operations following a frac pack and/or maintainweight down on tool during a frac pack.

An Exemplary Embodiment of a Tool

FIG. 3 shows the swivel of the present application within the casing ram140. Unlike the prior art tools Mako MAPTool™ and Deltascope® that areconfigured to fit within an annular blowout preventer, the tool of FIGS.1 and 3 has an outer diameter of the outer housing 30 which isconfigured to fit a casing ram. While such outer diameters may varydepending upon the casing ram and application, a typical outer diameterof the outer housing 30 may be from about 9.5 to about 10 inches andpreferably 9 ⅝ inches as opposed to 9.18 inches for prior art toolsconfigured for an annular blowout preventer. Similarly, the length ofthe outer housing of the tool of FIGS. 1 and 3 varies from the prior artin that the length is configured to fit a casing ram. Thus, length ofthe outer housing of the instant tools is generally shorter than priorart tools. The aforementioned modifications allow for the tools of theinstant application to be employed within a casing ram withoutsubstantially interfering with the function of components such asassociated casing shear rams and variable bore rams.

In another embodiment, the inner mandrel of the tool in FIG. 3 furthercomprises a locator recess configured to facilitate placement of theswivel within a casing ram. The depiction on the left side of FIG. 3 isan exploded depiction of the top of the mandrel of the device shown inthe casing ram. As shown, there is a recessed portion wherein the outerdiameter is smaller. This recessed portion or offset may facilitatelocating the outer housing of the tool across the casing rams in adesired position. That is, the recessed portion may be configured to fitwithin the annular blowout preventer. The size of the outer diameter ofthe mandrel and the recessed portion may vary depending upon theapplication. In some embodiments, the outer diameter may be about 7inches while the recessed portion may be about 5 ⅞ inches. That is, theouter diameter at the recessed portion may be from about 80 to about 85%of the mandrel outer diameter.

In some embodiments the following process steps may be employed:

-   Build special Inner Mandrel with locator recess-   Close Annular BOP on recess-   PU to against recess upset to space Outer Housing across Casing Rams-   Close Casing Rams-   Open Annular BOP-   Slack-off to release Inner Mandrel latch-   Run in hole ±60'-   Close Test Rams-   Perform pressure test on Deltascope® Tool between Test Rams and    Casing Rams-   Continue running in hole

What is claimed is:
 1. A swivel insertable into a casing ram of aworkstring, the swivel comprising: an inner mandrel having an upper endsection and a lower end section configured to be operably connectableand rotatable with an upper workstring section and a lower workstringsection, the inner mandrel comprising a longitudinal passage forming acontinuation of a passage in the workstring; and an outer housing havingan outer diameter and a length and wherein the outer housing isconfigured to seal the inner mandrel inside the outer housing; whereinthe inner mandrel is configured to slide up and down the outer housingand rotate within the outer housing; and wherein the outer diameter ofthe outer housing and the length of the outer housing is configured tofit a casing ram while allowing the function of associated casing shearrams and variable bore rams.
 2. The swivel of claim 1 wherein the innermandrel further comprises a locator recess configured to facilitateplacement of the swivel within a casing ram.